I also had Xpel professionally installed which included door cups. Soul Red.
Didn't do it myself, but have had it done on many cars during paint protection film applications.
The factory XPel location does the installations for me (including on my 30th Anniversary Miata that's there as I write this).
Door cups were done on all cars; including a few white vehicles and I've never had a yellowing issue.
Additionally, I keep my cars very clean, so no issue with dirt building up around the film edges.
I also had Xpel professionally installed which included door cups. Soul Red.
Has Xpel completely prevented chips for you guys?